Revivification of decolorizing adsorbents



April 1, 1941. R. P. FERGUSON ETA; 2,236,679

REVI IVIFICATION OF DECOLORIZING ADSORBENTS Filed Sept. 27, 1938 DISPLAc nvc. u u/b 5 OIL Hen Tflv a COIL. I MIXER 52' 9 COOLER Hazel-i;.2721; l' W wv LIQUID TANK ANK WASH LIQUID 17 vezc'avlsnar WASH LIQUID 11 1/ 2VIVIFI OUTLET M T/LTER CAKE 4 4- 7 Q I I Bu [1/ I Patented Apr. 1,1941 BEVIVIFIOATION 0F DECOLORJZING ADSOBBENTS Robert P. Ferguson,Oranford, and Frederick W. Schumacher, Mountainside, N. J., assignors toStandard Oil Development Company, a corporation of Delaware ApplicationSeptember 27, 1938, Serial No. 231,866

' 8 Claims. (01. 252-479) The present invention is concerned with thereviviiication of various adsorbents used in the decolorization of oils.The reactivation oiEv these materials in accordance with the process ofthe present invention is accomplished by treating the same with water,aqueous solutions, or other liquids immiscible with oil, at elevatedtemperatures and pressures.

It is well known in the art to decolorize mineral, vegetable, and animaloils with various adsorbents, as for example, fullers earth, such asAttapulgus or Floridin clays, acid activated clays such as Super Filtroland Tonsil, bauxites such as Porocel, synthetic materials such asMagnesol, and bone char. In these processes, the oil is contacted withthe adsorbent either by the percolation filtration process or by thecontact filtration process. The adsorbentand oil are contacted undervarious temperature and pressure conditions adapted to secure themaximum efliciency in the removal of color bodies. The adsorbent is thenremoved from the treated oil and is in many cases discarded since it isrelatively expensive to reactivate or reviviiy. However, severalprocesses of reactivating these materials have been employed. Forexample, it is known to wash spent clays with solvents such as naphtha,benzol, ketones, esters or combinations of these various solvents, toremove the adsorbed oil and color bodies and then to remove the naphthaor other solvent. It is also known to Various adsorbents alsodeteriorate at reactiva- F iiid immiscible with oil rather than by aprocess of dissolving these materials.

The process of our invention securing these desirable results may bereadily understood by reference to the attached drawing showing, onemodification of the same. For the purpose or the description, it isassumed the adsorbent is a spent clay which has been used for theremoval of color bodies from petroleum oil.

Spent clay is introduced into mixer 3 by means of line I. A suflicientquantity of displacing liquid, as for example water, is introduced intomixer 3 by means of line 2. The clay and liquid are thoroughly mixed in3 and are then passed through suitable heating equipment 4, in which thetemperature is raised to above 220 F. Suflicient pressure is maintainedon the equipment so that the displacing medium remains in a liquidcondition. The heated clay slurry is then introduced into pressuresettling drum 5, in which drum the clay is allowed to settle from thedisplacing medium and the oil phase. The oil phase may be removed fromthe. top of pressure drum 5 by means of line 6 which contains thedisplaced oil and color bodies. The displacing medium is withdrawn frompressure drum 5 from a point somewhat below the interface between theoil phase and the displacing medium by means of line 1. The displacingliquid may be recycled to mixer 3 by means of line 2. The wet clay iswithdrawn from pressure settling drum 5 by means of line 8 throughcooler 9 and separated from excess liquids in filter press It. The claymay be used after this treatment and is withdrawn by means of line Hthrough drying oven ii. In drying oven [2 the clay may be dried to anydesirable moisture content. The separated displacing liquid is returnedthrough line 13 and may be recycled through mixer 3. By the processdescribed,- complete displacement of the oil and color bodies from thespent clay is secured by heating with water at elevated temperatures andpressures. However, with various oils, some of the displaced materialdoes not floatto the surface but remains occluded in the clay mass.Under these conditions, it is desirable to wash the clay in filter IIwith various washing solutions. The washing liquids are secured fromwash liquid storages 2|, 2i, and 22 and.are introduced into II by meansof line H, and withdrawn by means or line l5. The washing liquid may besubsequently separated from the small amount of occluded color bodies bydistilling in equipment It, removing the overhead by means of line H andthe oil and color bodies'by means of line ll. It desirable, washingliquid may be recycled by means of line IS. The washed filter cake iswithdrawn from II by means of line H and dryed in oven H.

1 by washing with light naphtha.

water or aqueous solutions of other substances such as soaps, alkalies,acids, ketones, phenols, alcohols, and the like. Any displacing liquidhaving desirable physical properties and which is immiscible with theoil and color bodies at the temperatures and pressures employed issuitable. The preferred solutions are, however, aqueous solutionscontaining at least 50% water. Especially desirable solutions aresolutions containing from 96 to 98% water and containing 2% acid.

The volume of displacing liquid employed per volume of clay beingrevivified will depend upon the particular displacing medium employed aswell as upon the type and character of the clay. In general, it ispreferred to use from 5 to 50 gallons of displacing liquid per 100 lbs.of clay being revivified.

The temperature at which the clay.is contacted with the displacingsolution likewise will vary over a wide range. In general, the-clay iscontacted with the displacing liquid at a temperature in the range fromabout 220 to 710 F. Especially desirable results are secured when theclay is contacted with the displacing solution at a temperature in therange from about 350 to 550 F. The pressure employed in all cases shouldbe suflicient to keep the displacing medium in a liquid condition, andthus will depend upon the vapor pressure of the displacing liquidemployed and upon the temperature of contact.

After the oil has been displaced from the clay by means of a suitabledisplacing medium, the respective layers are withdrawn as previouslydescribed. The clay slurry is preferably cooled and then filtered; Theclay is then withdrawn from the filter and suitably dried to a desirablemoisture content. In gen? dry the clay to about 20-30% volatile content,the volatile content being determined by heating the clay at 1650 F. forhour at atmospheric pressure.

ral, it is preferred to Although clay may besuita-bly revivified in theabove-described manner, especially desirable results are secured bywashing the clay cake on the filter with various washing liquids. Thesewashing liquids tend to cleanse the clay of minute,

entrained displaced color bodies and oil.

Various materials may be employed as washing solutions, as for example,a substance selected from the class of alcohols, esters, ketones,

light petroleum fractions boiling below about 550 F., ethers, and thelike. Desirable washing substances are, for example, alcohols andnaphthas. It has been found that excellent results aresecured, forexample, by first washing the clay on the filter with isopropyl alcoholfollowed The quantity of washing solution employed will depend upon theparticular washing solution used, as well as upon the type of clay beingrevivified, and also upon the displacing solution employed.

In general, it is preferred to use .from 10 to 100 gallons of washingsolution per 100 lbs. of clay. For example, when washing with alcoholfollowed by washing with naphtha, it is desirable to use from 5 to 20gallons of alcohol per 100 lbs. of clay and from 10 to 30 gallons ofnaphtha per 100 lbs. of clay. I

A particularly important modification of the present invention is thatin certain operations it may be desirable to acidify the clay inreviviiication. Thus, in this type of operation, for example, the colorbodies and oil could be displaced by water or an aqueous solution in 5and the stratified layer removed as described. The

aesaevo clay would be filtered in i0 followed by washing with alcoholwithdrawn from 2| and then washed with naphtha from 22. The filter cakecould then be readily acidified with an acid wash from 2|.

This process could also be modified and the operation conducted, forexample, by displacing color bodies and oil in 5 by means of water oraqueous solution, the stratified layer separated and removed'asdescribed above and the clay filtered in IQ. The clay could then bewashed with an acidified solution as, for example, with acidifiedalcohol followed by washing with light naphtha. Another 'modificationmay be, for example, to displace the color bodies and oil from the clayin 5 by means of an acidified aqueous solution. In this operation theclay would be separated from the stratified layer as described and takendirectly to drying oven l2, thus bypassing the filtering or the washingoperations or both. Particularly desirable results are secured in thisoperation by means of a solution comprising from about 50-60% water,40-50% alcohol, and 24% acid.

In order to further illustrate the invention the following examples aregiven. These examples are given merely for illustrative purposes andshould not be construed as limiting the invention in any mannerwhatsoever.

Exulrtr: 1-

Table 1 c1 7 r h s F'lt 1 Rcovemd 8 I68 llPOI' 1 I0 uper y FiltrolPounds clay/gal o 0.25 0. 315 o. 5 o. 5 Temperature of contact (F.)- 425425 425 425 Color finished oil (in R.)-- s m m 12% 9% From the abovedata, it may readily be seen that the revivified clay, when used in theproportion of 0.5 lb. of clay per gallon of oil, at 425 F., gaveapproximately of the improvement secured with fresh clay.

EXAMPLE 2 Solvent extracted distillate stock having an A. P. I. gravityof 29.4, flash of 450 F., and a viscosity of F. of 325 Universal Sayboltseconds was contacted with 0.5 lb. per gallon of Super Filtrol clay at425 F. The spent clay from this operation was then revivified by variousmodifications of the process of the present invention. In someoperations the displacing liquid was water; in other operations waterwas used as a displacing liquid and various washing solutions wereemployed. In further operations the displacing liquids were aqueoussolutions containing small percentages of other substances, as forexample, j sulfuric acid, acetone, alcohol, and the like. Variouswashing solutions were i employed in these latter operations; Theresults of including an acidified liquid wash. Operation 5' thefollowing data:

steps. Operation 13 demonstrates that an orsame success as an inorganicacid. data, I

Table 4 I Eificirny. 11:01" Gage rcs- Second Displncing liquid tgl sure,fbsrl First wash liquid wash Third wash liquid :Fgfigggg:

liquid l Sq m p volatile matter=100%) l 510 750 Alc0liol l- Naphtha2%aqueous sulfuric acid. 71 2 510 750 Alcohol wash from do Acid washfrom 1 79 s '420 750 n c7 EXAIIPLI 3 of these operations are summarizedbelow. Various oilswere treated with Super Filtrol Table 2 Efllgizincm'pra Displac- Gage prescan compare Operato fresh Sn .1- on i; llqllld mg teinp. susred, ilnbsJ First wash l quid Second wash liquid Third washliquid Film] g alent volatile matter content) 510 750 52 510 750 Naphtha61 510 750 do 2% aqueous sul- 99 [uric acid. 510 750 Benzol do r 108 510750 2%aqueous acid Isopropyl alcolioL. Naphtha 113 510 150 Naphtha 3 510750 L ca 510 750 2% aqueous acid 73 420 r50 as 420 750 Naphtha 114 420 7124 510 750 Isopropyl alcohol Naphtha -t 2% agueous acetic 102 The abovedata clearly demonstrates that apand revlvifled after each treatment.The clay preclable revivification of spent clay is secured bywasrevlvlfled byheatlng with 98% water and 2% displacing adsorbed oiland color bodies with 30 acid at a temperature of 510 Rand a pressure ofwater at elevated temperatures :and pressures. It I 750 lbs/sq. in:Following the treatment, the clay may also be seen that somewhat betterreviviflcawas given isopropyl alcohol and naphtha washes tlon is securedif the clay is subsequently washed equivalent to 10 gals. and 15 gals.respectively, witha washing solution, as for example, naphtha. per 100poundsof spent clay. The efllciency of Operations 3 and 4 demonstratethe desirability 3-3 the clay after each reviviflcation may be seen byTable 3 1 El1icicncy. r it? res uper Clay employed Oil stock contactedFiltrol or e uivalent v0 tile matter= 100%) ,Fresh Super Filtrol Acidtreated Mid-Continent residuum 100 Reactivated clay from Contact No. 1sotliilrliiit extracted Mid-Continent dis- 109 e. Reactivated clay fromContact No. 2,.-. Pennsylvania neutral distillate 103 Reactivated clayfrom Contact No. 3 o 100 Reactivated clay from Contact No. 4 wig-181?extracted Mid-Continent dis- 97 e. Reactivated clay [min Contact No. 5do 89 shows that especially desirable results are se- ExAi rPLr: 4

cured by a particular sequence of washing steps after displacement ofthe color bodies with water. contactm g solvent extracted Mid-Contlnentdisoperagmn 6 demgnsgates 'z gf g pz 5.3 tillate was revivified by usingvarious displacing 2:: g gzgf g 1 :2 zfi g g liquids, followed byWashing with suitable. solvents to remove the occluded color bodies and:g gs f ii g a ggg figg fi oil. The efliciency of the revivified claydeter- 8 3 5 g Sp g f a hm mined by again contacting the solventextracted mums sequences W s g (i0 distillate with 0.5 lb./gallon of thepartially dried v clay secured from these various reviviflcatiori gameand may be used wlth approximately the processes may readily be seen bythe following Spent Super Filtrol clay previously used for The abovedata demonstrate that alcohol and said wash may be reused withoutfurther purification. Operations 3 and 4 demonstrate that the displacingliquids may be reused without additional purification.

EXAMPLE 5 Table 5 Efficiency. per- 1 cent Iiollowing Disp acwas ing pro-No. ing 53 i cedure (fresh temp., S in Super Filtrol F. of equivalentvolatile mattcr=l%) The process of the present invention is verydesirable in that the clay is revivified by displacing the color bodiesand oil occluded in the clay. This is a distinct advantage over the useof solvents to remove these deleterious materials. In accordance withthe present process, the clay is not subjected to temperature conditionswhich are detrimental to its decolorizing efliciency. Furthermore, byoperating in accordance with our invention, it is possible to replace toany desired amount the effective moisture content of the clay. Inaddition, there is practically 100% recovery of the oil which iscommonly lost through clay soakagethus further enhancing the economicsof the present process.

The present process may be readily applied to the revivification ofdecolorizing and deodorizing adsorbents, utilized in the refinement ofanimal, vegetable, and mineral oils, as for example, in the treatment ofany petroleum fractions such as naphthas, lubricating oils, petroleumwaxes, pe-

troleum resins, and the like. Although the pres- 4 ant process isparticularly directed to the revivification of decolorizing clays usedin the treatment of petroleum products, it is readily used for therevivification of other adsorbents, such as synthetic decolorizinganddeodorizing substances, bone char, and the like.

The above invention is not to be limited by any theory or mode ofoperation but only in and by the following claims in which it isintended to claim all novelty in so far as the prior art permits.

We claim: V

1. A process of revivifying spent decolorizing clays comprising treatingsaid clays with an aqueous solution at a temperature in the range from220 to 700 F. under suflicient pressure of at least 140 pounds persquare inch to maintain the solution in a liquid condition, holding theclay under these conditions to effect substantial displacement of oiland color bodies, separating the clay from the aqueous reactivatingsolution, washing the clay with a solvent adapted to remove the aqueoussolution and occluded impurities, washing the clay with an aqueoussolution containing approximately 2 to 4% of sulfuric acid, removing thewashed clay and drying the same.

2. Improved process of reactivating spent decolorizing clay comprisingtreating said clay with an aqueous solution at a temperature in therange from 350 to 550 F. and at a pressure of at least 140 pounds persquare inch adapted to maintain the solution in the liquid condition,holding the clay under these conditions to efiect substantially completedisplacement of the oil and color bodies, separating the displacingsolution and the impurities, subjecting said separated clay to a washingoperation with a solvent adapted to remove occluded portions of the oiland color bodies, separating the solvent, subjecting the separated clayto a washing operation with an aqueous solution containing from 2 to 4%of sulfuric acid, removing the clay and drying the same.

3. Process in accordance with claim 2 in which said aqueous washingsolution comprises a mixture of alcohol, water and acid.

4. Process of revivifying spent decolorizing clay comprising treatingsaid clay with liquid water at a temperature in the range from about 220to 700 F. and at a pressure of at least 140 pounds per square inch,maintaining the clay and water under these conditions until substantialdisplacement of the oil and color bodies from the clay is secured,separating the stratified displacing liquid and the layer of colorbodies and oil from the clay, removing the clay and filtering the same,then subjecting said clay to an alcohol wash, a naphtha wash, and anacidic wash successively, removing the clay and drying the same to anoptimum moisture content.

5. Process in accordance with claim 4 in which said temperature is inthe range from about 350 to 550 F.

6. Process of revivifying spent decolorizing clay comprising subjectingsaid clay to a treatment with liquid water at a temperature in the rangefrom about 350 to 550 F. and at a pressure of at least pounds per squareinch for a time sufficient to secure substantially complete displacementof color bodies and oil, separating the stratified layers from the clay,filtering the clay and then washing the same with a washing solutioncomprising acid and alcohol followed by washing the same with naphtha,removing the clay and drying to an optimum moisture content.

7. Process in accordance with claim 6 in which said washing solutioncomprising acid and alcohol contains approximately 2% acid.

8. Improved process of revivifying spent decolorizing clay comprisingsubjecting the clay to treatment with a liquid aqueous solution at atemperature in the range from about 350 to 550 F. and at a pressure inthe range of 140 to 750 pounds per square inch for a time sufiicient tosecure substantially complete displacement of the color bodies and oil,separating the clay from the stratified layers, subjecting the separatedclay to a treatment with an aqueous solution containingapproximately 2to 4% of an acid and drying the same to an optimum moisture content.

ROBERT P. FERGUSON. FREDERICK W. SCHUMACHER.

